Method for actuating a tappet in a lifting or clamping device, especially for folding sheet metals in car manufacture

ABSTRACT

Device for actuating a slide or tappet ( 1 ) in a lifting or clamping device, especially for folding sheet metals in automobile manufacture. A slide ( 1 ) is guided in a base stand ( 3 ) and can be driven. The slide ( 1 ) supports the folding bed and presses the sheet metals to be folded against stationary folding tools. The slide ( 1 ) is supported on at least one wedge surface ( 7 ) which can be adjusted in an electromotive manner.

FIELD OF THE INVENTION

The present invention pertains to a device for actuating a slide in alifting or clamping device, especially for folding sheet metals inautomobile manufacture, wherein a slide that is guided in a base and canbe driven with a folding bed lying on it presses the sheet metals to befolded against stationary folding tools.

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 5,150,508 discloses a prior-art device of the typedescribed in the introduction. The folding stroke and the needed foldingforce are brought about by a central hydraulic cylinder located underthe slide. In DE 197 47 291 another embodiment of this type has acompressed air cushion located under the slide. The slide moves thefolding bed and the workpiece (body sheet metal) located therein againstthe stationary prefolding and finishing folding tools, which arefastened to displaceable and pivotable means.

SUMMARY AND OBJECTS OF THE INVENTION

The object of the present invention is to do away with hydraulic orpneumatic systems for generating and transmitting the necessary force.

This object is accomplished by the slide with its side facing theworkpiece being supported on at least one wedge surface, which can beadjusted by means of an electric motor. In particular, a wedge having awedge surface can be guided at the base, which wedge can be adjusted bymeans of an electric motor. The wedge is preferably adjustableessentially at right angles to the working direction of the slide.

In a preferred embodiment of the present invention, a spindle nut isarranged at the wedge for a spindle that is guided therein and can bedriven by means of an electric motor. The wedge is adjusted during therotation of the spindle and the slide is thus raised or lowered. In aspace-saving arrangement, the spindle nut is accommodated in a recess ofthe wedge. The recess is preferably a stepped hole, whose section withthe greater diameter accommodates the spindle nut and in whose sectionwith the small diameter the end of the spindle can move. The spindle nutpreferably has a recirculating ball thread.

The spindle can be connected to an electric motor via a coupling. Theelectric motor is preferably controlled by a frequency converter. Atransmission may be advantageously intercalated between the electricmotor and the coupling. The spindle may be guided in an self-aligningroller thrust bearing on the motor side.

Furthermore, it has proved to be favorable for two wedges with wedgesurfaces to be arranged in opposite directions being able to be adjustedsimultaneously in opposite directions via a threaded drive withleft-hand and right-hand threads and to act on a wedge connected to theslide with associated wedge surfaces. During the rotation of thespindle, which is driven by an electric motor, the two wedges are pushedtogether or moved apart by the left-hand and right-hand threads of thespindle via the spindle nuts. The consequence of this is that the wedgeconnected to the slide is moved correspondingly to and fro.

The device, which is preferably called an electromechanical liftingunit, can be used, among other things, in the fields of clampingtechnique, folding and hemming technique and also in special areas ofmaterials handling technology.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic partially sectional view showing a device forfolding body sheet metals in automobile manufacture using a wedge;

FIG. 2 is a schematic partially sectional view showing anotherembodiment using two wedges displaceable in opposite directions in thelower position of the wedge; and

FIG. 3 is a schematic partially sectional view showing the embodimentaccording to FIG. 2 in the upper position of the wedge.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in particular, FIG. 1 shows a slide 1, whichcan be moved vertically up and down and carries on the top side afolding bed 2 for the body sheet metals to be folded. Stationary foldingtools, not shown, are located above the folding bed 2. The slide 1 isguided in a base 3 between sliding plates 4. A horizontally adjustablewedge 5, which is guided on sliding plates 6 arranged at the base 3, islocated below the slide 1. The slide 1 is supported with a sliding shoe8 on an oblique wedge surface 7 facing the slide 1.

A recess 9 is designed as a stepped hole in the embodiment being shown.The recess 9 extends from a front side of the wedge 5, and a spindle nut10 is inserted axially nondisplaceably and nonrotatably in the sectionof the stepped hole with the larger diameter. The spindle nut 10 isdesigned as a recirculating ball thread in the embodiment being shown. Aspindle 11, whose free end can move into the section with the smallerdiameter of the recess 9, is guided in the spindle nut 10.

The other end of the spindle 11 is guided in a self-aligning rollerthrust bearing 12, which is arranged in a bearing housing 13 connectedto the base 3. A coupling 14 has an outlet or output side connected tothe spindle 11 and has an inlet or driven side connected to the drivenshaft of a transmission 15. The coupling 14 can in turn be driven with afrequency converter-controlled electric motor 16. The coupling 14 islocated in the bearing housing 13.

In case of a corresponding direction of rotation of the electric motor16, the spindle 11 is put into rotation after engaging the coupling 14.Due to the transmission in the spindle nut 10, the wedge 5 moves in thehorizontal direction and displaces the slide 1 in the vertical directionin the process.

In FIGS. 2 and 3 a left lower wedge 17 and a right lower wedge 18 areshown. The left lower wedge 17 and the right lower wedge 18 haverespective wedge surfaces 7 sloped in opposite directions. Thesesurfaces 7 can be moved in opposite directions by means of a commonthreaded drive 20 with left-hand and right-hand threads. The threadeddrive 20 is driven by a common electric motor 16 via the coupling 14 andhas the bearings 23 and 24 on the end side. To lift the slide 1, the twowedges 17, 18 are moved simultaneously toward one another by means ofthe threaded drive 20, and the corresponding wedge surfaces 7 of thewedges 17, 18 slide on the wedge surfaces 25 of the upper wedge 19 andthus lift the slide 1. After reversing the direction of rotation of thethreaded drive 20, the wedges 17, 18 are moved apart and the slide 1 isthus lowered.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A lifting device for folding sheet metal inautomobile manufacture, the device comprising: a base; a slide guided insaid base; a slide wedge connected to said slide and having a wedgesurface; two base wedges with oppositely arranged wedge surfaces, saidslide and said slide wedge is supported on said two base wedges; athreaded drive with an anti-clockwise and clockwise thread connected tosaid two wedges to simultaneously adjust said two base wedges inopposite directions; an electric motor driving said threaded drive.
 2. Adevice in accordance with claim 1, further comprising: a stationaryfolding tool mounted on said base; a folding bed mounted on said slide,said motor rotating said threaded drive to move said folding bed towardsaid stationary folding tool and process a sheet arranged between saidfolding bed and said stationary folding tool.
 3. A device in accordancewith claim 1, wherein said two base wedges are guided on said base.
 4. Adevice in accordance with claim 1, wherein said two wedges areadjustable essentially at right angles to a working direction of saidslide.
 5. A device in accordance with claim 1, wherein: said threadeddrive includes a spindle nut arranged in each of said two wedges; and aspindle guided in said spindle nuts and driven by said electric motor.6. A device in accordance with claim 4, wherein each of the spindle nutsare accommodated in a recess of said two wedges.
 7. A device inaccordance with claim 4, wherein each of the spindle nuts have arecirculating ball thread.
 8. A device in accordance with claim 5,wherein each of the recesses is a stepped hole.
 9. A device inaccordance with claim 4, further comprising a coupling wherein thespindle is connected to said electric motor via said coupling.
 10. Adevice in accordance with claim 8, further comprising a transmissionbetween the electric motor and the coupling.
 11. A device in accordancewith claim 1, wherein: said threaded drive includes a spindle and aspindle guide with a self-aligning roller thrust bearing wherein saidspindle is guided on a motor side in said self-aligning roller thrustbearing.
 12. A device for processing a sheet, the device comprising: abase; a stationary folding tool mounted on said base; a folding bedmovably mounted along said base in a first direction, said folding bedand said stationary folding tool being receivable of the sheets to beprocessed; a first wedge movably mounted between said folding bed andsaid base, said first wedge being movable in a second directionangularly spaced from said first direction; a second wedge movablymounted between said folding bed and said base, said second wedge beingmovable in said second direction, said first and second wedges havingwedge surfaces sloped in opposite directions and interacting with saidfolding bed to move said folding bed in said first direction when saidfirst and second wedges are moved in said second direction; a threadeddrive connected to said first wedge with a first thread, said threadeddrive being connected to said second wedge with a second thread, saidfirst thread being in an opposite direction from said first thread,rotation of said threaded drive moving said first and second wedgestoward and away from each other; a motor connected to said thread drivefor rotating said threaded drive to move said first and second wedgeswhich then move said folding bed in said first direction toward saidstationary folding tool and process the sheet arranged between saidfolding bed and said stationary folding tool.
 13. A device in accordancewith claim 12, wherein said first and second base wedges are guided onsaid.
 14. A device in accordance with claim 12, wherein: said threadeddrive includes a spindle nut arranged in each of said first and secondbase wedges, and a spindle guided in each said spindle nut andelectrically driven by said motor.
 15. A device in accordance with claim14, wherein said each spindle nut is accommodated in a recess of saidfirst and second base wedges.
 16. A device in accordance with claim 14,wherein said each spindle nut has a recirculating ball thread.
 17. Adevice in accordance with claim 15, wherein each said recess is astepped hole.
 18. A device in accordance with claim 14, furthercomprising a coupling and comprising a transmission between said motorand said coupling wherein said spindle is connected to said motor viasaid coupling and said transmission.
 19. A device in accordance withclaim 14, further comprising a spindle guide with a self-aligning rollerthrust bearing wherein said spindle is guided on a motor side in saidself-aligning roller thrust bearing.